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Volume 56, Issue 1
Displaying 1-7 of 7 articles from this issue
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A.F.M. Saiful ISLAM, Yoshiaki KITAYA, Hiroaki HIRAI, Masanori YANASE, ...2000 Volume 56 Issue 1 Pages 1-9
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSWe placed rice husk charcoal masses with different dimensions into soil ridges (500mm in width and 250mm in height) for promoting soil aeration in a wet lowland, and investigated sweetpotato growth and the soil gas component. The widths of the rice husk charcoal masses were 0 (control), 75, 150, 225 and 300mm, and the thickness of each mass was 120mm. The material was covered with 80mm thick soil. Water depth between the ridges was kept at 20mm throughout the growing period to maintain a wet soil condition. The dry weight of the total phytomass was greater in the 150 and 225mm width treatments than in the other treatments. The dry weights of shoot and the tuberous roots in the 150mm width treatment were 0.6 and 1.4 times, respectively, those in the control. The number, length and diameter of tuberous roots were greatest in the 150mm width treatment. The carbon dioxide concentration in the soil ridge was almost double in the control compared with the 150, 225 and 300mm width treatments. The lower carbon dioxide concentration in the soil ridges and an adequate soil volume for supplying water and nutrients to the roots would partly account for the better development of tuberous roots in the 150 and 225mm width treatments.View full abstractDownload PDF (1122K) -
Hiromitsu KANNO, Jianqing XU, Kiyoshi OZAWA2000 Volume 56 Issue 1 Pages 11-23
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe meteorological features of Yamase (cold northeasterly wind) and sea breezes are investigated for the summer of 1997, and their invasion to the hilly mountain area on the Pacific side are discussed.
When sea breezes are present, solar radiation is generally large, but the temperature decreases on the coastal region of the Pacific due to the cold air masses brought by the wind from the ocean. During the Yamase period, both solar radiation and temperature decrease, and the lowest solar radiation areas are found on the eastern side of the mountains.
The Yamase process has three stages: early, peak, and late. In the peak stage, there was a mixed layer from the surface to about 900hPa (1, 000m) and easterly winds reached above 800hPa (2, 000m). In the early and late stages there were stable layers at lower height with easterly winds. In spite of the different vertical profiles of stratification and easterly wind, clouds were formed at the same height (below 1, 500-2, 000m) through the three stages.
Northeastern Japan was covered by a large and homogeneous air mass during the Yamase period, however, below 800hPa relative humidity and potential temperatures differed between the Pacific and Japan Sea sides. These differences were due to modifications of the low level air mass, by processes such as damming up of air masses by mountains and heating from the surface.
In the study area (hilly mountain area), during the sea breeze period, the low temperatures were confined to the coastal area and the meteorological conditions differed from inland area. On the other hand, the potential temperatures were almost the same from the coastal to inland areas during the Yamase period. In this case, the air mass with mixed layers invaded from the coast to the inland with very small and/or no air mass modification.View full abstractDownload PDF (5748K) -
Takamitsu SATO, Shinichi URANO, Tomomi TAKEDA2000 Volume 56 Issue 1 Pages 25-30
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSTo clarify the effects of the width and density of a shelterbelt on wind speed reduction, field observations of wind speed distribution were carried out around shelterbelts of different widths and plant area densities (PADs). The results are as follows.
(1) For shelterbelts with the same width, the wind speed on the leeward of the shelterbelt decreased as PAD increased. On the other hand, for shelterbelts with the same PAD, the wind speed on the leeward of the shelterbelt decreased as the width increased. Consequently, width and PAD were confirmed to be factors of the shelterbelt structure that influence wind speed.
(2) In the relationships between the minimum wind speed and width or PAD, there were great variations in the data. However, a strong correlation was found between the minimum wind speed and HPAI, determined as the total surface area of plants (one side only) within a horizontal cylinder of unit cross-section. Consequently, HPAI is a valid factor with which to evaluate the effects of shelterbelt structure on wind speed.View full abstractDownload PDF (732K) -
Andrea COOK, George L. VOURLITIS, Yoshinobu HARAZONO2000 Volume 56 Issue 1 Pages 31-40
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSJapan contains an estimated 3, 865 mineral springs, 82 of which are CO2 emitting springs and the 54 cold springs (less than 20°C) of them can potentially be used as surrogates for assessing the long-term (decades-centuries-millennia) effects of elevated CO2 on natural vegetation. Because some mineral springs can emit CO2 over centuries-millennia, they represent the only feasible means for investigating the long-term effects of elevated CO2 on natural vegetation, and depending on output, can provide a free source of CO2 for short-term elevated CO2 manipulative experiments. Little is known regarding the location of CO2 springs in Japan, rates of CO2 emission, and feasibility for conducting elevated CO2 research on natural vegetation.
In March of 1998, twelve mineral springs in the Oita, Gifu, and Toyama Prefectures of Japan were surveyed for their potential for studying the effects of long-term elevated CO2 on the physiology of natural vegetation. Analysis of atmospheric gas samples and the 14C content of leaf material indicate that the vegetation surrounding these springs had been exposed to elevated levels of CO2. Most of the springs were not suitable for elevated CO2 research because they were either impacted by human activities (e.g., were pumped, surrounded by cement, or altered for bathing), or were not surrounded by intact natural vegetation. However, one spring (Rindo, Toyama Prefecture) emitted large rates of CO2 within a relatively undisturbed deciduous forest, and thus, represents one of the only known opportunities to study the direct effects of long-term elevated CO2 exposure on deciduous forests. With ca. 40 more known CO2 springs to be surveyed, the potential for conducting elevated CO2 research using CO2 springs in Japan is higher than most other parts of the world.View full abstractDownload PDF (1325K) -
Jun SUZUKI2000 Volume 56 Issue 1 Pages 41-45
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (476K) -
Yoshiaki KITAYA, Kazuhiko KOBAYASHI2000 Volume 56 Issue 1 Pages 47-50
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
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The Development of New Measurement Technique by Young Researcher in the Cultivated LandWorking Group Meteorological Improvement Studies f2000 Volume 56 Issue 1 Pages 51-53
Published: March 10, 2000
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (365K)
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